The embodiments of the present invention relate to an image reading apparatus and more particularly, to an image reading apparatus such as a color copier and a color scanner used to read a transparent film.
Conventionally, the same amount of light is irradiated to all the films that are to be read regardless of the films' transmission factor. Therefore, considerations are not made even when the range of light transmission factor of the films is very wide. This causes inadequacy of a white balance adjustment. Especially, when a color positive film with a bad light transmission factor is read, the tone of the image that is required for reading is far different from that of the original film.